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167 lines
3 KiB
Markdown
167 lines
3 KiB
Markdown
---
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navigation_title: "Nested"
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mapped_pages:
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- https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-nested-aggregation.html
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---
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# Nested aggregation [search-aggregations-bucket-nested-aggregation]
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A special single bucket aggregation that enables aggregating nested documents.
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For example, lets say we have an index of products, and each product holds the list of resellers - each having its own price for the product. The mapping could look like:
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$$$nested-aggregation-example$$$
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```console
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PUT /products
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{
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"mappings": {
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"properties": {
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"resellers": { <1>
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"type": "nested",
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"properties": {
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"reseller": {
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"type": "keyword"
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},
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"price": {
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"type": "double"
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}
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}
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}
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}
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}
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}
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```
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1. `resellers` is an array that holds nested documents.
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The following request adds a product with two resellers:
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```console
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PUT /products/_doc/0?refresh
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{
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"name": "LED TV", <1>
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"resellers": [
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{
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"reseller": "companyA",
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"price": 350
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},
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{
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"reseller": "companyB",
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"price": 500
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}
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]
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}
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```
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1. We are using a dynamic mapping for the `name` attribute.
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The following request returns the minimum price a product can be purchased for:
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```console
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GET /products/_search?size=0
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{
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"query": {
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"match": {
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"name": "led tv"
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}
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},
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"aggs": {
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"resellers": {
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"nested": {
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"path": "resellers"
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},
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"aggs": {
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"min_price": {
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"min": {
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"field": "resellers.price"
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}
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}
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}
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}
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}
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}
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```
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As you can see above, the nested aggregation requires the `path` of the nested documents within the top level documents. Then one can define any type of aggregation over these nested documents.
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Response:
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```console-result
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{
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...
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"aggregations": {
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"resellers": {
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"doc_count": 2,
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"min_price": {
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"value": 350.0
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}
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}
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}
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}
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```
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You can use a [`filter`](/reference/aggregations/search-aggregations-bucket-filter-aggregation.md) sub-aggregation to return results for a specific reseller.
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```console
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GET /products/_search?size=0
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{
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"query": {
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"match": {
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"name": "led tv"
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}
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},
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"aggs": {
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"resellers": {
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"nested": {
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"path": "resellers"
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},
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"aggs": {
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"filter_reseller": {
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"filter": {
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"bool": {
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"filter": [
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{
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"term": {
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"resellers.reseller": "companyB"
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}
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}
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]
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}
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},
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"aggs": {
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"min_price": {
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"min": {
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"field": "resellers.price"
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}
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}
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}
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}
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}
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}
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}
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}
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```
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The search returns:
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```console-result
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{
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...
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"aggregations": {
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"resellers": {
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"doc_count": 2,
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"filter_reseller": {
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"doc_count": 1,
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"min_price": {
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"value": 500.0
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}
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}
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}
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}
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}
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```
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